Wool-like artificial fibers and process of making same



Patented Feb. 22, 1938 UNITED STATES PATENT OFFICE WOOL-LIKE ARTIFICIAL FIBERS AND PROC- ESS OF MAKING SAME I. G. Farbenindustrie Aktiengesellschaft,

Frankfort-on-the-Main, Germany No Drawing. Application January 5, 1934, Se-

rial No. 705,474. 1933 4 Claims.

Our present invention relates to wool-like artificial fibers and to a process of making same.

Artificial fibers consisting (at the end of the manufacturing processes) of regenerated cellu- 5 lose, that is copper silk or viscose silk, exhibit when dried in the usual manner physical and tinctorial properties other than in the wet state. For instance a copper silk which is not yet dried possesses a high affinity to substantive dyestuifs and might be dyed in deep shades already at low temperatures. This affinity is, however, diminished by the usual drying processes especially when higher temperatures are used. For this reason owing to unequal drying effects unequal .5 dyeings are obtained and soft useful products result only with the addition of textile expedients when the hitherto known drying processes are used. Thereby it is proved that the usual drying operations alter essentially the properties 20 of the fibers.

We have now found that by a special drying operation (which is per so already known and used for other materials) not only the said deterioration can be avoided or diminished but that 25 also other wise the properties of the fibers are substantially changed and the goods thus treated represent a new kind of artificial fibers unknown hitherto.

In accordance with the present invention we 30 treat wet artificial fibers which are (depending on the spinning process used) freed from metallic compounds, acids or sulfur and may be bleached and washed, with organic liquids miscible with water.

35 Especially suitable for our present process are copper silk or copper-silk like fibers. The latter may be obtained by processes difierent from the copper-silk process, and are distinguished in a wet state, similar to the copper-silk itself, by a 40 high affinity to substantive dyestuffs and a small affinity to basic dyestuffs.

This drying process is advantageously carried out with a fibrous material newly spun, not yet being dried, with an organic liquid easy to be re- 45 covered, at a relatively low temperature, especially room temperature, and to such a degree that the treated fibers still contain the so-called molecular water usually present in commercial brands.

The new process runs in a very simple way especially as some complicated operations necessary in the processes, hitherto used, that is, washing, soaping and so on, may be dispensed with 55 and simultaneously with the drying operation In Germany January 1'7,

special effects may be produced by the addition of certain preparations, that is sizing matters.

The new fibers produced by our process are distinguished by a remarkable softness, a warm touch and a crepe and curly form. These properties render them similar to animal fibers such as wool or natural silk in as high a degree as unknown hitherto. They show furthermore useful values of elasticity and strength, especially a favourable elasticity.

These new and useful properties of our products are obtained, as we suppose, because the water present in the wet starting fibers is removed in an exceedingly mild way without destroying, rendering sticky or otherwise injuring their surface and therefore their mechanical consistence, but with maintaining their original structure.

In order to further illustrate our invention the following examples are given; but we wish it, however, to be understood that our invention is not limited to the particular products or reacting conditions stated therein.

Example 1 Newly spun copper-silk which is entirely freed from copper and acids is introduced, immediately after being centrifugated or pressed, into a sufflcient amount of alcohol (say of 95% strength). Then it is taken out of the alcohol bath, advantageously centrifugated and freed from the remaining alcohol by an aftertreatment with for instance carbon tetrachloride or ether. The solvent last used is removed from the fibers by evaporation and may be recoverd.

The fibers thus obtained show the aforesaid properties.

In an analogous manner other liquids customary for removing water, even containing some water themselves, may be used, single or several combined, simultaneously or subsequently. The solvents are advantageously used in the liquid state.

This process may be used with the same success when the fibers are continuously spun.

Example 2 Wet copper silk of the like state of manufacture as that used in Example 1 is treated with acetone and then with carbon tetrachloride. These solvents may be applied successively or according to a counter-current process. In order to obtain special effects the last portion of the solvent may be mixed with suitable agents, for

instance, sizing, impregnating or other preparations.

In an analogous manner also viscose yields by a similar single or continuous process products of like favorable properties when the regenerated cellulose, as to physical properties, is rendered similar to copper silk for instance by means of the spinning operation: see Kunstseide, by Dr. 0. Faust, 4th and 5th Ed., 1931, pages. 99 and 218.

Example 3 Newly spun cellulose ribbon consisting of a great number of single filaments of for instance copper silk, immediately after having passed the usual cold or hot treating baths, is pressed, centrifugated or squeezed in order to free it mechanically from Water. Then it is introduced into a bath of a low content of alcohol (say 30%). From the said bath the fiber bunch is introduced into further baths of an increasing concentration of alcohol. The baths may be connected by means of overflows and provided between one another with further means for squeezing or scraping off. When the material has left the bath of the highest concentration of alcohol, the adhering alcohol is removed by mechanical means so that only a small remaining portion of the alcohol is to be removed by evaporation. The goods thus obtained are reeled up. As a sudden shrinking is avoided by the low concentration of the first alcoholic bath, the goods exhibit especially favorable qualities.

We claim:

1. Process of manufacturing artificial fibers which comprises dehydrating newly spun wet regenerated cellulose fibers having the dyeing prop erties of copper silk at room temperature in several successive baths containing liquid alcohol of an increasing concentration, the dehydration being interrupted when the treated fibers still contain the so-called molecular water usually present in commercial brands,

2. Process of manufacturing artificial fibers which comprises dehydrating newly spun wet copper silk at room temperature in several successive baths containing liquid alcohol of an increasing concentration, the dehydration being interrupted when the treated fibers still contain the so-called molecular water usually present in commercial brands.

3. Wool-like artificial fibers substantially consisting of regenerated cellulose showing the dyeing properties of copper silk and being characterized by a high afilnity to substantive dyestuffs and a small afiinity to basic dyestuffs, which fibers are distinguished by a remarkable softness, a warm feeling and a crepe or curly form which properties render them similar to animal fibers, said artificial fiber product having been produced by the process of claim 1.

4. Wool-like artificial fibers consisting of cop per silk distinguished by a remarkable softness, a warm feeling and a crepe or curly form which properties render them similar to animal fibers, said artificial fiber product having been produced by the process of claim 2.

ARTHUR VON WEINBERG. HANNS REIN. OTTO EISENHUT. 

